"But what do you expect? I mean, when you take away after-school programmes for children and Meals on wheels for the poor people, that's not what you call 'making America great again'. Come on!"

Schwarzenegger, who recently took over from Mr Trump as the host of The Apprentice, added: "I mean who is advising you?

Let me give you some advice: Go to a middle school, to Hart Middle School right in Washington six miles away from the White House. I'll take you there so you can see the fantastic work that they're doing for these children."

His comments came just hours after former Mexican President Vicente Fox Quesada launched his own Twitter attack on the former real-estate mogul.

"If this were TV, you'd be fired," he wrote. "America, tell it like it is: Donald, you're fired!"

Mr Trump's approval rating dropped to a new low of 37 per cent, according to a Gallup poll released over the weekend.

The change came as his Republican Party released their poorly-received budget proposal that saw hundreds-of-millions of dollars worth of funding cut to key social and education programmes.

The president's plans included the complete elimination of the $3 billion (£2.4 billion) Community Development Block Grant program, which funds community projects like Meals on Wheels and housing assistance.

The Woodrow Wilson International Centre for Scholars, which provides scholarships and fellowships in social sciences and humanities, is set to lose out on $11 million (£8.87 million) worth of funding.

Funding for International Education programmes, which run a variety of exchanges, migrant schools and special education services abroad, also looks likely to have $7 million (£5.65 million) cut.

Mr Trump's approval rating has since moved up slightly to 39 per cent. However, it remains the lowest of any president for at least 70 years at this stage of his first term.

It came as FBI director James Comey testified under oath that Mr Trump had falsely accused his predecessor Barack Obama of wiretapping his headquarters during last year's presidential campaign.